Slate Roof Repair

There are 2 general categories of slate roofs- newer and older. Newer slate roofs need little to no maintenance. Whereas older slate roofs need periodic inspections and maintenance. Problemsoccur on older roofs for 2 main reasons: types of slate and flashing failure. The harder, longer-lastingslate (100+ years) is quarried in New York and Vermont. The softer, less durable slate(70-100 years) is quarried in Pennsylvania and Virginia.

The least durable, the Pennsylvania black slate, only has a life span of 50-70 years. After 20-3-years the top layer wears off, delamination begins and over time the slates start crumbling. Effective repair is nearly impossible as more slate is damaged in attempting a repair. In nearlyall cases with PA black slate, the end result is a total roof replacement.

With harder, longer-lasting slate, issues arise from flashing failures at valleys, around chimneysand walls, at vent pipes and other generations. Tin (no longer available) and copper are the mostcommon metals used in re-flashing these details, although .032-gauge aluminum is an acceptablesubstitute for copper. Flashing details can be repaired without removing the whole roof; however,this type of work requires a roofer experienced in working with slate.

Flashing details that are still in good condition often need a fresh application of polyurethanesealant - a material that remains flexible over time. Other areas that may require sealinginclude ridges and hips. Also, lower-sloped roofs are prone to failure because people will walk onthem and break the slates. Then non-professionals perform poor repairs because the areas areaccessible. The roof will still leak and this creates more traffic, resulting in a downward spiralof deterioration and ending with the slate roof needing replacement. The periodic inspection andmaintenance of the slate by qualified, experienced personnel is essential to extending the life of the roof. Prescott Roofing, with over 114 years of experience to fall back on, is most qualifiedto address any issues with a slate roof.